Internal combustion takes place in the engine body, which is the part of the engine that contains the air intake and air discharge sections, and the piston cylinders. The internal combustion process heats the engine body, and therefore an exterior body, such as a cover, is generally attached to the engine to prevent someone from touching the engine body directly. Rotation of the crankshaft drives the drive wheel (drive pulley); and the exterior body may be equipped to also cover the drive wheel and the cooling fan to prevent a person from touching these components directly.
The following Patent Document 1 discloses a fan cover, which is one of the above types of exterior body. In conventional art, the entire surface of the cooling air intake on the fan cover is provided with a dustproof body that rotates, or that reciprocates across the entire cooling air intake. The dustproof body rotates at a high speed together with the cooling fan provided inside the fan cover, to prevent debris from clogging the cooling air intake.